Patents by Inventor Noritaka ISHIHARA
Noritaka ISHIHARA has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 9123573Abstract: An oxide semiconductor stacked film which does not easily cause a variation in electrical characteristics of a transistor and has high stability is provided. Further, a transistor which includes the oxide semiconductor stacked film in its channel formation region and has stable electrical characteristics is provided. An oxide semiconductor stacked film includes a first oxide semiconductor layer, a second oxide semiconductor layer, and a third oxide semiconductor layer which are sequentially stacked and each of which contains indium, gallium, and zinc. The content percentage of indium in the second oxide semiconductor layer is higher than that in the first oxide semiconductor layer and the third oxide semiconductor layer, and the absorption coefficient of the oxide semiconductor stacked film, which is measured by the CPM, is lower than or equal to 3×10?3/cm in an energy range of 1.5 eV to 2.3 eV.Type: GrantFiled: October 29, 2014Date of Patent: September 1, 2015Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Shunpei Yamazaki, Masashi Tsubuku, Ryosuke Watanabe, Masashi Oota, Noritaka Ishihara, Koki Inoue
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Publication number: 20150243738Abstract: Favorable electrical characteristics are given to a semiconductor device. Furthermore, a semiconductor device having high reliability is provided. One embodiment of the present invention is an oxide semiconductor film having a plurality of electron diffraction patterns which are observed in such a manner that a surface where the oxide semiconductor film is formed is irradiated with an electron beam having a probe diameter whose half-width is 1 nm. The plurality of electron diffraction patterns include 50 or more electron diffraction patterns which are observed in different areas, the sum of the percentage of first electron diffraction patterns and the percentage of second electron diffraction patterns accounts for 100%, the first electron diffraction patterns account for 90% or more, the first electron diffraction pattern includes observed points which indicates that a c-axis is oriented in a direction substantially perpendicular to the surface where the oxide semiconductor film is formed.Type: ApplicationFiled: February 19, 2015Publication date: August 27, 2015Inventors: Akihisa SHIMOMURA, Yasumasa YAMANE, Yuhei SATO, Takahisa ISHIYAMA, Kenichi OKAZAKI, Chiho KAWANABE, Masashi OOTA, Noritaka ISHIHARA
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Publication number: 20150236165Abstract: Reducing hydrogen concentration in a channel formation region of an oxide semiconductor is important in stabilizing threshold voltage of a transistor including an oxide semiconductor and improving reliability. Hence, hydrogen is attracted from the oxide semiconductor and trapped in a region of an insulating film which overlaps with a source region and a drain region of the oxide semiconductor. Impurities such as argon, nitrogen, carbon, phosphorus, or boron are added to the region of the insulating film which overlaps with the source region and the drain region of the oxide semiconductor, thereby generating a defect. Hydrogen in the oxide semiconductor is attracted to the defect in the insulating film. The defect in the insulating film is stabilized by the presence of hydrogen.Type: ApplicationFiled: April 30, 2015Publication date: August 20, 2015Inventors: Masashi TSUBUKU, Yusuke NONAKA, Noritaka ISHIHARA, Masashi OOTA, Hideyuki KISHIDA
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Publication number: 20150155169Abstract: To provide a method for manufacturing a semiconductor device including an oxide semiconductor film having conductivity, or a method for manufacturing a semiconductor device including an oxide semiconductor film having a light-transmitting property and conductivity. The method for manufacturing a semiconductor device includes the steps of forming an oxide semiconductor film over a first insulating film, performing first heat treatment in an atmosphere where oxygen contained in the oxide semiconductor film is released, and performing second heat treatment in a hydrogen-containing atmosphere, so that an oxide semiconductor film having conductivity is formed.Type: ApplicationFiled: November 24, 2014Publication date: June 4, 2015Inventors: Masashi OOTA, Noritaka ISHIHARA, Motoki NAKASHIMA, Yoichi KUROSAWA, Shunpei YAMAZAKI, Yasuharu HOSAKA, Toshimitsu OBONAI, Junichi KOEZUKA
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Patent number: 9035305Abstract: Reducing hydrogen concentration in a channel formation region of an oxide semiconductor is important in stabilizing threshold voltage of a transistor including an oxide semiconductor and improving reliability. Hence, hydrogen is attracted from the oxide semiconductor and trapped in a region of an insulating film which overlaps with a source region and a drain region of the oxide semiconductor. Impurities such as argon, nitrogen, carbon, phosphorus, or boron are added to the region of the insulating film which overlaps with the source region and the drain region of the oxide semiconductor, thereby generating a defect. Hydrogen in the oxide semiconductor is attracted to the defect in the insulating film. The defect in the insulating film is stabilized by the presence of hydrogen.Type: GrantFiled: September 25, 2014Date of Patent: May 19, 2015Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Masashi Tsubuku, Yusuke Nonaka, Noritaka Ishihara, Masashi Oota, Hideyuki Kishida
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Publication number: 20150084043Abstract: Defects in an oxide semiconductor film are reduced in a semiconductor device including the oxide semiconductor film. The electrical characteristics of a semiconductor device including an oxide semiconductor film are improved. The reliability of a semiconductor device including an oxide semiconductor film is improved. A semiconductor device including an oxide semiconductor layer; a metal oxide layer in contact with the oxide semiconductor layer, the metal oxide layer including an In-M oxide (M is Ti, Ga, Y, Zr, La, Ce, Nd, or Hf); and a conductive layer in contact with the metal oxide layer, the conductive layer including copper, aluminum, gold, or silver is provided. In the semiconductor device, y/(x+y) is greater than or equal to 0.75 and less than 1 where the atomic ratio of In to M included in the metal oxide layer is In:M=x:y.Type: ApplicationFiled: September 15, 2014Publication date: March 26, 2015Inventors: Noritaka ISHIHARA, Masashi OOTA, Masashi TSUBUKU, Masami JINTYOU, Yukinori SHIMA, Junichi KOEZUKA, Yasuharu HOSAKA, Shunpei YAMAZAKI
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Publication number: 20150048368Abstract: An oxide semiconductor stacked film which does not easily cause a variation in electrical characteristics of a transistor and has high stability is provided. Further, a transistor which includes the oxide semiconductor stacked film in its channel formation region and has stable electrical characteristics is provided. An oxide semiconductor stacked film includes a first oxide semiconductor layer, a second oxide semiconductor layer, and a third oxide semiconductor layer which are sequentially stacked and each of which contains indium, gallium, and zinc. The content percentage of indium in the second oxide semiconductor layer is higher than that in the first oxide semiconductor layer and the third oxide semiconductor layer, and the absorption coefficient of the oxide semiconductor stacked film, which is measured by the CPM, is lower than or equal to 3×10?3/cm in an energy range of 1.5 eV to 2.3 eV.Type: ApplicationFiled: October 29, 2014Publication date: February 19, 2015Inventors: Shunpei YAMAZAKI, Masashi TSUBUKU, Ryosuke WATANABE, Masashi OOTA, Noritaka ISHIHARA, Koki INOUE
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Publication number: 20150048365Abstract: Reducing hydrogen concentration in a channel formation region of an oxide semiconductor is important in stabilizing threshold voltage of a transistor including an oxide semiconductor and improving reliability. Hence, hydrogen is attracted from the oxide semiconductor and trapped in a region of an insulating film which overlaps with a source region and a drain region of the oxide semiconductor. Impurities such as argon, nitrogen, carbon, phosphorus, or boron are added to the region of the insulating film which overlaps with the source region and the drain region of the oxide semiconductor, thereby generating a defect. Hydrogen in the oxide semiconductor is attracted to the defect in the insulating film. The defect in the insulating film is stabilized by the presence of hydrogen.Type: ApplicationFiled: September 25, 2014Publication date: February 19, 2015Inventors: Masashi TSUBUKU, Yusuke NONAKA, Noritaka ISHIHARA, Masashi OOTA, Hideyuki KISHIDA
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Patent number: 8890159Abstract: An oxide semiconductor stacked film which does not easily cause a variation in electrical characteristics of a transistor and has high stability is provided. Further, a transistor which includes the oxide semiconductor stacked film in its channel formation region and has stable electrical characteristics is provided. An oxide semiconductor stacked film includes a first oxide semiconductor layer, a second oxide semiconductor layer, and a third oxide semiconductor layer which are sequentially stacked and each of which contains indium, gallium, and zinc. The content percentage of indium in the second oxide semiconductor layer is higher than that in the first oxide semiconductor layer and the third oxide semiconductor layer, and the absorption coefficient of the oxide semiconductor stacked film, which is measured by the CPM, is lower than or equal to 3×10?3/cm in an energy range of 1.5 eV to 2.3 eV.Type: GrantFiled: July 29, 2013Date of Patent: November 18, 2014Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Shunpei Yamazaki, Masashi Tsubuku, Ryosuke Watanabe, Masashi Oota, Noritaka Ishihara, Koki Inoue
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Publication number: 20140326991Abstract: A semiconductor device in which variation in electrical characteristics between transistors is reduced is provided. A transistor where a channel is formed in an oxide semiconductor layer is included, and a concentration of carriers contained in a region where the channel is formed in the oxide semiconductor layer is lower than or equal to 1×1015/cm3, preferably lower than or equal to 1×1013/cm3, more preferably lower than or equal to 1×1011/cm3, whereby an energy barrier height which electrons flowing between a source and a drain should go over converges at a constant value. In this manner, a semiconductor device in which variation in the electrical characteristics between the transistors is inhibited is provided.Type: ApplicationFiled: April 22, 2014Publication date: November 6, 2014Applicant: Semiconductor Energy Laboratory Co., Ltd.Inventors: Daisuke MATSUBAYASHI, Toshimitsu OBONAI, Noritaka ISHIHARA, Shunpei YAMAZAKI
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Patent number: 8860023Abstract: Reducing hydrogen concentration in a channel formation region of an oxide semiconductor is important in stabilizing threshold voltage of a transistor including an oxide semiconductor and improving reliability. Hence, hydrogen is attracted from the oxide semiconductor and trapped in a region of an insulating film which overlaps with a source region and a drain region of the oxide semiconductor. Impurities such as argon, nitrogen, carbon, phosphorus, or boron are added to the region of the insulating film which overlaps with the source region and the drain region of the oxide semiconductor, thereby generating a defect. Hydrogen in the oxide semiconductor is attracted to the defect in the insulating film. The defect in the insulating film is stabilized by the presence of hydrogen.Type: GrantFiled: April 25, 2013Date of Patent: October 14, 2014Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Masashi Tsubuku, Yusuke Nonaka, Noritaka Ishihara, Masashi Oota, Hideyuki Kishida
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Publication number: 20140241978Abstract: A method for manufacturing a sputtering target with which an oxide semiconductor film with a small amount of defects can be formed is provided. Alternatively, an oxide semiconductor film with a small amount of defects is formed. A method for manufacturing a sputtering target is provided, which includes the steps of: forming a polycrystalline In-M-Zn oxide (M represents a metal chosen among aluminum, titanium, gallium, yttrium, zirconium, lanthanum, cesium, neodymium, and hafnium) powder by mixing, sintering, and grinding indium oxide, an oxide of the metal, and zinc oxide; forming a mixture by mixing the polycrystalline In-M-Zn oxide powder and a zinc oxide powder; forming a compact by compacting the mixture; and sintering the compact.Type: ApplicationFiled: February 24, 2014Publication date: August 28, 2014Applicant: Semiconductor Energy Laboratory Co., Ltd.Inventors: Shunpei YAMAZAKI, Masashi TSUBUKU, Masashi OOTA, Yoichi KUROSAWA, Noritaka ISHIHARA
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Publication number: 20140183530Abstract: A semiconductor device includes an oxide semiconductor layer over a first oxide layer; first source and drain electrodes over the oxide semiconductor layer; second source and drain electrodes over the first source and drain electrodes respectively; a second oxide layer over the first source and drain electrodes; a gate insulating layer over the second source and drain electrodes and the second oxide layer; and a gate electrode overlapping the oxide semiconductor layer with the gate insulating layer provided therebetween. The structure in which the oxide semiconductor layer is sandwiched by the oxide layers can suppress the entry of impurities into the oxide semiconductor layer. The structure in which the oxide semiconductor layer is contacting with the source and drain electrodes can prevent increasing resistance between the source and the drain comparing one in which an oxide semiconductor layer is electrically connected to source and drain electrodes through an oxide layer.Type: ApplicationFiled: December 27, 2013Publication date: July 3, 2014Applicant: SEMICONDUCTOR ENERGY LABORATORY CO., LTD.Inventors: Shunpei Yamazaki, Shinpei Matsuda, Masashi Oota, Noritaka Ishihara
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Publication number: 20140124776Abstract: A metal oxide film including a crystal part and having highly stable physical properties is provided. The size of the crystal part is less than or equal to 10 nm, which allows the observation of circumferentially arranged spots in a nanobeam electron diffraction pattern of the cross section of the metal oxide film when the measurement area is greater than or equal to 5 nm? and less than or equal to 10 nm?.Type: ApplicationFiled: November 5, 2013Publication date: May 8, 2014Applicant: SEMICONDUCTORS ENERGY LABORATORY CO., LTD.Inventors: Masahiro Takahashi, Takuya Hirohashi, Masashi Tsubuku, Noritaka Ishihara, Masashi Oota
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Publication number: 20140113405Abstract: To form an oxide semiconductor film with a low density of localized levels. To improve electric characteristics of a semiconductor device including the oxide semiconductor. After oxygen is added to an oxide film containing In or Ga in contact with an oxide semiconductor film functioning as a channel, heat treatment is performed to make oxygen in the oxide film containing In or Ga transfer to the oxide semiconductor film functioning as a channel, so that the amount of oxygen vacancies in the oxide semiconductor film is reduced. Further, an oxide film containing In or Ga is formed, oxygen is added to the oxide film, an oxide semiconductor film is formed over the oxide film, and then heat treatment is performed.Type: ApplicationFiled: October 17, 2013Publication date: April 24, 2014Applicant: Semiconductor Energy Laboratory Co., Ltd.Inventors: Masashi TSUBUKU, Ryosuke WATANABE, Noritaka ISHIHARA, Masashi OOTA
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Publication number: 20140034946Abstract: An oxide semiconductor stacked film which does not easily cause a variation in electrical characteristics of a transistor and has high stability is provided. Further, a transistor which includes the oxide semiconductor stacked film in its channel formation region and has stable electrical characteristics is provided. An oxide semiconductor stacked film includes a first oxide semiconductor layer, a second oxide semiconductor layer, and a third oxide semiconductor layer which are sequentially stacked and each of which contains indium, gallium, and zinc. The content percentage of indium in the second oxide semiconductor layer is higher than that in the first oxide semiconductor layer and the third oxide semiconductor layer, and the absorption coefficient of the oxide semiconductor stacked film, which is measured by the CPM, is lower than or equal to 3×10?3/cm in an energy range of 1.5 eV to 2.3 eV.Type: ApplicationFiled: July 29, 2013Publication date: February 6, 2014Applicant: Semiconductor Energy Laboratory Co., Ltd.Inventors: Shunpei YAMAZAKI, Masashi TSUBUKU, Ryosuke WATANABE, Masashi OOTA, Noritaka ISHIHARA, Koki INOUE
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Publication number: 20130292675Abstract: Reducing hydrogen concentration in a channel formation region of an oxide semiconductor is important in stabilizing threshold voltage of a transistor including an oxide semiconductor and improving reliability. Hence, hydrogen is attracted from the oxide semiconductor and trapped in a region of an insulating film which overlaps with a source region and a drain region of the oxide semiconductor. Impurities such as argon, nitrogen, carbon, phosphorus, or boron are added to the region of the insulating film which overlaps with the source region and the drain region of the oxide semiconductor, thereby generating a defect. Hydrogen in the oxide semiconductor is attracted to the defect in the insulating film. The defect in the insulating film is stabilized by the presence of hydrogen.Type: ApplicationFiled: April 25, 2013Publication date: November 7, 2013Inventors: Masashi TSUBUKU, Yusuke NONAKA, Noritaka ISHIHARA, Masashi OOTA, Hideyuki KISHIDA